58 THE HORSE 



came from homogeneous blood. For an extended dis- 

 cussion of inbreeding, see Chapter XII. 



A grade is the progeny of a full -blood and a 

 "nondescript," the latter term meaning, in this con- 

 nection, an animal usually having little or no improved 

 blood and of no authenticated and recorded ancestry. 

 The term "high grade" is usually applied to animals 

 which have derived seven -eighths or more of their blood 

 from the full-blooded ancestry. This term is seldom 

 used to indicate the lineage of horses, they being 

 specifically termed half-blood, three -fourths blood, and 

 so on. 



Subbreeds are formed by selecting, from a breed, 

 two or more animals which may vary slightly from the 

 usual type of the breed, and then by accentuating 

 the differences by means of improved food, manage- 

 ment and selection. A good illustration of a subbreed 

 is the Delaine Merino sheep. This subbreed was 

 started by selecting animals that produced wool longer 

 than the average. These were put under better con- 

 ditions and when the offspring varied toward wool 

 of a longer staple and yet of good quality, they were 

 preserved. Those were discarded which did not show 

 improvement along the line desired and also those 

 which tended to revert to the shorter -wooled type. If 

 the increase in the length of wool had been secured by 

 a cross with one of the long-wooled breeds, then the 

 term "cross-breed" would have been appropriate. 



A cross-bred animal is the progeny of two distinct 

 breeds, as the White Plymouth Rock, which was prob- 

 ably produced by crossing the White Leghorn with the 



